Lathe carriage drive



Dec. 4, 1962 w. A. KlMsl-:Y

LATI-IE CARRIAGE DRIVE 4 Sheets-Sheet l Filed April 13, 1959 INVEN T OR/f/Mif/ a-J fw AT T ORNEYS Dec. 4, 1962 w. A. KlMsEY 3,066,553

LATHE CARRIAGE DRIVE Filed April 13, 1959 4 Sheets-Sheet 2 lltu INVENTOR fie-4 Wm MM A. /f//wsff/ ATTORNEYS j Dec. 4, 1962 w. A. KlMsEYLATHE CARRIAGE DRIVE 4 Sheets-Sheet 3 Filed April 13 Dec. 4, 1962 w. A.KlMsi-:Y

LATHR CARRIAGE: DRIVE 4 Sheets-Sheet 4 Filed April 13, 1959 L5 los@ 4513,666,553 LATHE CARRIAGE DRIVE Wiiiiam A. Iimsey, Cincinnati, Ghia,assigner to The R. K. Le Blond Machine Tool Company, Cincinnati, Ohio, acorporation of Deiaware Filed Apr. 13, i959, Ser. No. $186,129 4 Slaims.(Cl. 'f7- 3) This invention relates to a drive for carriages or lathes,and is particularly concerned with the drive arrangement for extremelylarge lathe carriages and like machine tool members that move along amachine bed.

In connection with known machine elements such as lathe carriages andalso slides which are of conventional sizes, adequate control of thesliding movements can be had by a feed rod or lead screw as is done inmost lathe structures. In some cases, however, the machine structure isof such a large size that a lead screw or the like is insucient andundesirable for carrying the tremendous thrust loads that are to beimposed thereon in sliding the member along its ways and particularlywhere the member is at the same time loaded heavily by the cuttingaction of the tools carried thereby.

-In still other cases the carriage or slidable member may becomeextremely wide between the Ways on which it is supported and a carriageor slide or" this nature is quite apt to tend to crab along the ways ifdriven at a single point such as would be `the case in utilizing a leadscrew or feed rod.

ln other cases, the bed supporting the carriage or slidable element, andthis is particularly the case with lathes, may become extremely long, upto 90 or l0() feet or more, and under these circumstances it becomesexpensive and diicult lto produce a lead screw of the proper length andaccuracy to drive the carriage or slidable member the full length of itstravel along such au elongated bed.

Further, a lead screw or feed rod elongated to this extreme length wouldhave considerable liexibility in torsion and would also sag between itssupports unless it were made extremely large and heavy.

Having the foregoing in mind, it is a primary object of the presentinvention to provide a drive for an extremely wide carriage or slide ina machine tool or the like which will eliminate crabbing or cockin g ofthe slide or carriage on its suppontin g ways.

A still further object of this invention is the provision of a drivearrangement ttor the carriage or a slidable element of an extremely longmachine tool which will eliminate the necessity of long feed rods orlead screws.

A still further object of this invention is the provision of a drivearrangement for a lathe carriage or the like which is carriedsubstantially entirely on the carriage thereby greatly simplifying theconstruction and arrangement of the lathe bed.

It is also an object of this invention to provide a drive for a lathecarriage or the like in which the driving forces are distributed aboutthe carriage permitting the development of extremely high driving forcesbeyond what could be established by use of a lead screw or the like.

rI'hese and other objects and advantages will become more apparent uponreference to the accompanying drawings in which:

FIGURE l is an elevational view of one end of a long lathe structureshowing a boring carriage provided with a drive arrangement according tothis invention and also showing one bar support for supporting theboring bar at a point spaced along the bed from the boring carriage,

FIGURE 2 is an elevational view similar to FIGURE l but shows the otherend of the lathe which includes the rotary face plate that drives thework being operated and a steady rest structure that supports the work,

ih Patented Eea. 4, H5952 FIGURE 3 is an elevational view looking infrom the right end of the lathe as indicated by the arrow 3 on FIGURE l,

FIGURE 4 is a sectional view indicated by line 4 4 on FIGURE 3 showing adrive train between a hydraulic drive motor and a pinion driven thereby,

FIGURE 5 is a sectional view indicated by line S-S on FIGURES l and 4showing the drive train and including a transverse connection extendingthrough the carriage which includes a planetary gear diiferential fordividing the power from the hydraulic motor between the two pinicns atthe opposite sides of the carriage,

F IGURE 6 is a section through the planetary gear differential and isindicated by line 6-6 on FIGURE 5,

FIGURE 7 is a perspective view partly broken away showing the planetarygear diifcrential,

FIGURE 8 is a diagrammatic representation of a hydraulic circuit foractuating the hydraulic drive motors of the boring carriage, and

FIGURE 9 is a diagrammatic representation of an electric control circuitthat could be employed for controlling the operation of the machine.

Referring to the drawings more in detail, the machine in connection withwhich the present invention is illustrated is a lathe comprising a bediti, the right end of which is seen in FIGURE l and the left end ofwhich is seen in FIGURE 2. This bed may be extremely long up to, say,13G feet or more, and may advantageously be made up of sections on theorder of about 30 feet in length. The bed sections are bolted togetierto orm the completed bed. As will be seen in FIGURE 3, the bed isprovided `with way portions l2 for slidably receiving steady rests,support bars, and a boring carriage means. These ways are hardened andground and extend the full length of the bed.

Mounted on the bed at the left end thereof is a headstock arrangement Mthat includes a tace plate lr6 adapted for being driven in rotation by adrive motor (not shown) via belt or chain drive means extending into thecover 18. Face plate `le is adapted for gripping the end of a workpiece2b that extends through a plurality of spaced steady rest means 22 thatare movably mounted on the bed it?. These steady rests, which may be ofa conventional nature, support the workpiece Zit for rotation about itscentral axis. There may be provided one or more of the steady rests,depending upon the length of the workpiece being operated.

At the other end of the bed l@ and sliclably supported on ways l2 is aboring carriage 203 that includes an upstanding part 26 adapted forxedly supporting the end of a tool 28. Tool 28 extends letwardly throughthe bar supports 3) which are movably mounted on the lathe bed and ofwhich supports there may be a plurality spaced along the bed, dependingupon the length of the tool being employed. These supports preferablyinclude motors so that they can be traversed along the bed and inaddition are arranged so that as the boring carriage advances toward thehead end of the bed, the bar supports will be moved along thereby, andthereafter when the boring carriage retracts the bar supports will beretracted thereby until they reach the positions at which they aresupposed to be located at the beginning of the boring operation.

In addition, and not shown in the drawings, in about the middle of thebed there is a bar support. that sealingly engages the end of the workand also sealingly engages the boring bar and through which support thecoolant for the boring operation being carried out is supplied.

The boring carriage 24 may have detachably mounted thereon a drivinghead 32 for driving small boring bars. This unit has its own drivingmotor 34, and, as mentioned,

cheeses can readily be detached from the boring carriage by utilizingthe lift hooks 36. rl`his unit likewise has its own controls asindicated at 3S and is thus operable independently of the remainder ofthe machine.

The support 26 that receives the end of the larger boring bar may beavailed of for supporting gauges dit to indicate the operatingconditions of the machine such as the speed and horse power of thespindle and the feed speed of the boring bar and the like. There mayalso be carried on member 2d control push buttons generally indicated atd2. This makes up a centralized con-.trol panel from which the spindleand bar, rate of feed and traverse, and the coolant pumps for themachine can be controlled.

in the machine illustrated, the lathe carriage is on the order of 6 feetfrom side to side, and because of this extreme width the carriage has atendency to crab along the bed when it is advanced by any usual type ofdrive means. According to the present invention this tendency of thecarriage to crab along the bed is entirely eliminated by mounting alongeach side of the bed a rack 4d eX- tending along the bed for the fulldistance of travel of the boring carriage, and which racks are engagedby pinions distributed about the boring carriage with the pinions beinginterconnected and driven so as to advance the carriage along the lathebed without twisting or crabbing. This is accomplished by arranging thepinions adjacent the corners of the carriage and interconnecting thepinions in pairs through differential units to hydraulic drive motors.

Reference to FlGURES l, 4, and 5 will show that the boring carriage 2dhas a pair of dependent housings i6 carried thereon, each of whichhousings carries a hydraulic motor d8. Each hydraulic motor 4S hasmounted on its output shaft a bevel gear 5@ meshing with another bevelgear 52 to which is fixed a pinion :74. The bevel gear 52 and pinion 5dare rotatable on a shaft 56. Pinion Sd meshes with a gear 53 rotatableon shaft titl and fixed to a pini-on 62 that meshes with a gear 64rotatable on a shaft 66. Gear 64 has integral therewith a pinion 63meshing with a gear '7h rotatable on shaft of) and the same size as gear5S. Gear 7ta has fixed thereto a pinion 72 meshing with a gear 7drotatable on shaft 66 and the same size as gear 64. The describedarrangement provides for counter rotation of gears 64 and 7d at the samespeed when hydraulic motor dit pertaining thereto is energized.

Gear 64 meshes with another gear 76 rotatable on a shaft 7S and gear 74meshes with a gear di? the same size as gear 76 and also rotatable onshaft 7S. Gears 76 and t5@ have elements S2 of a jaw clutch on theirinner sides and slidably splined to shaft 7S between these elements is aclutch member Se having the other elements 86 of the said jaw clutch onits opposite sides. It will be evident that actuation of clutch member84 can be utilized for selectively coupling either of gears 76 or 8hwith shaft 7S, or for uncoupling the shaft from both of the said gears.

Shaft 73, and which shaft it will be noted in FlGURES l and 4 is locatedin the boring carriage above the upper level of bed le, extends into theregion of the center of the boring carriage and into a housing 83attached to the under side of the carirage. Within the housing andconnected to the end of shaft 78 as by a spline is a pinion 90 thatmeshes with a gear 92 in the housing which forms a part of a two parthollow planet carrier 94 journaled within the housing on theantifriction bearings 96.

The planet carrier referred to forms a part of a differential unit whichis illustrated in FIGURES 6 and 7 in addition to FIGURE Extending intohousing 83 from opposite sides thereof and on the axis of rotation ofplanet carrier 94 are the shafts 98 and litt?. Splined to the end ofshaft 93 within the planet carrier is a gear 162, and splined to the endof shaft fil@` within the planet carrier is a gear Hifi of thc same sizeas gear 362. Within the planet carrier and arranged in distributedrelation about the peripheries of gears lliiZ and ldd are a plurality ofpinion support shafts 1%. These support shafts carry the pinions 1%which rnesh with each other thus forming intermeshing pairs of pini-ons.Each pair of the pinions, however, consists of a first pinion meshingwith only one of gears N2 and Iltis and a second pinion meshing with theother of the gears. There are preferably three such pairs ofintermeshing pinions within the planet carrier.

Shaft 9d, which is splined to gear 62, extends into the housing 46 andis attached therein to gear 109 that meshes with gear liti fixed toshaft lf2. Shaft il?, extends out the inner wall of housing 46 and hasattached thereto a pinion lf3 running on rack Lid.

Similarly, shaft idd, which is attached to gear 1M, extends to the otherside of the carriage into a smaller housing fil!- carried by thecarriage and therein is attached to a gear lid meshing with gear figattached to shaft ft2@ corresponding With shaft M12 and having attachedto its inner end a pinion 122 meshing with the adjacent rack de.

rIhe arrangement is such that energization of hydraulic motor 4S willdrive through the gear train and the Adescribed differential and causethe two pinions 113 and E22 to rotate and provide equal thrusts at thefront corners of the carriage, thus causing the carriage to advancesmoothly along the lathe bed without any tendency for he carriage toknock or crab during its movements. The differential provides for anequal division of power between the pinions except upon any tendency ofthe carriage to crab, in which case the retarded corner receives greaterpower than the other thus offsetting the said crabbing tendency.

For some carriages the provision of two driving pinions is sufficientbut in the present case where the carriage is of substantial length aswell as width and embodies considerable weight and requires a highthrust during working operations, there is preferably provided pinionsat the rear corners of the carriage which are driven through anidentical gearing arrangement from the other of the hydraulic motors 4?.

'In addition to eliminating any tendency for the carriage to crab, thedescribed arrangement also eliminates long expensive lead screws andfeed rods, and there is only required the hydraulic lines 124 leading tothe hydraulic motors with suitable valve means being associatedtherewith to control the supply of uid to the motors.

The hydraulic circuit by means of which the motors d8 are operated isillustrated in FIGURE 8. In this figure pump i3d is driven by a motor132 so as to discharge fluid under pressure into a conduit i3d. Thisconduit leads to the inlet of a four-way reversing valve i3d having avalve member i358 normally urged by spring idf) into position to connectthe pressure conduit with conduit M2 while conduit lef-i is connectedwith an exhaust manifold 146. Energization of a solenoid S-l is operableto shift the valve member to reverse the laforementioned connections.

`Conduit fit/i2 leads through the parallel connected valve ldd and chokevalve i149 to one side of each of motors i8 and also to one port of atwo-way valve 150. Valve l5@ has a valve member 1.52 normally urged byspring 2154 t0 connect conduit 142 with exhaust manifold ldd, and thereis provided a solenoid S-Z energizable for shifting the valve memberinto position to block off conduit M2. Thus when no power is developedby the motors 48 there is no pressure in line E42. therefor, no heat isadded to the oil during idle periods.

Conduit 144 leads to a port of a two-way valve 156 having valve memberllit normally urged by a spring 159 into position to interruptcommunication between conduit ldd and conduit i60, and there is provideda solenoid S-I energizable for shifting valve member ld into position tointerconnect conduits ldd and idd, conduit 16) leading to the side ofmotors d8 opposite the connection thereto of conduit 142.

There is connected with conduit 142 a pressure switch 162 to detectpressure of a predetermined amount within the said conduit.

To obtain traverse of the carriage, solenoids S-1 and S-3 are energized.Solenoid S2 remains de-energized, with the solenoids so energized fluidpasses from conduit 134 to conduit 144 and thence to conduit 166 andthen through motors 4S to conduit 142, then through valve 15G toexhaust. This provides for rapid traversing movements of the boringcarriage in the feed direction. To obtain reduced speed for feedingmovements, solenoid S-2 is energized, and this disconnects conduit 142from the exhaust, and the fluid therefrom must instead pass throughchoke valve 149. This provides for feed movement of the boring carriage.The boring carriage can be halted at any time by de-energization ofsolenoids S-l, S-Z and S-3 which will interrupt the supply of iluid toconduit 16@ and block any discharge from conduit Mil. This alsounbloclrs lines 134 and 142 and allows free flow of lluid from pump totank.

Reverse movement of the boring carriage is had by energizing solenoidsS-2 and 8 3 leaving solenoid S-1 de-energized which provides for flow offluid from conduit 134 to conduit M2 and thence through check valve 148to one side of the hydraulic motors d, with the other side thereforebeing connected through conduits 169 and 144 with the exhaust manifoldM6. As before, movement of the boring carriage may be halted byde-energization of solenoids S-l, S-Z and S-3.

The change from traverse or feed movement to reverse may be accomplishedby a limit switch control, or by pressure switch 162, or pressure switch162 may be employed to cause automatic retraction of the boring carriagein event resistance beyond a pre-determined amount is encountered, whichcould indicate dulling of the cutting tool.

The arrangement of the present invention provides a convenient andeconomical manner in which large, heavy, wide carriages or slide memberscan be actuated along a machine bed so that the movement thereof isunder perfect control at all times and without there being any tendencyfor the carriage to twist on the ways which could cause sticking andcrabbing leading to excessive wear of the sliding machine parts and thecarrying out improperly of work operations.

The construction of the bed is simplified since it is not necessary topro-vide supports therein or driving arrangements therein for leadscrews or feed rolls. The entire carriage actuating mechanism includingthe drive motors and controls therefor are associated with the carriage,and the only thing that is provided on the bed are the elongated rackelements.

As to the diierential units which are employed, it will be evident thatthe gears 102 and N4 thereof form output members that are connected bythe shafts 93 and lill? with the gearing leading to the pinions thatengage the racks on the bed. Each gear 92 of the dierential units thencomprises an input member which, when driven, serves to supply equalpower to the output members 102 and ille of the diierential units.

FIGURE 9 diagrammatically illustrates one form of circuit in which thesolenoids Sl, S2 and S3 could be connected for effecting automaticcontrol of the machine, including automatic retraction of the carriageupon the encountering of a predetermined load thereby.

In FIGURE 9 there is a push button 2d@ which can be closed to energizerelay R1 having a holding circuit extending through a normally closedblade 262 of a relay R3. Relay R1 has blades that close when the relayis energized to bring about energization of solenoids S1 and S3 whichwill put the carriage on rapid traverse.

Another push button 204 is connected in circuit with a relay R2 so thatclosing of the push button will energize relay R2 and which has aholding circuit through another normally closed blade 206 of relay R3. Alimit switch LS1 is connected in by-passing relation to switch 204 sothat it can be tripped by the carriage at a predetermined point in itstravel to automatically initiate said movement of the carriage. Relay R2has a blade in circuit with solenoid S2 so that when the relay isenergized solenoid S2 will become energized along with solenoids S1 andS3 and the carriage will advance at feed rate.

A third push button 203 is provided which is in circuit with relay R3and which relay has a holding circuit through a limit switch L82 and isnormally closed by timer blade T1. Closing of push button 298 willenergize relay R3 which, through its blades 262 and 266 will de-energizerelays Rl and R2.

Blades of relay R3 in circuit with solenoids S2 and S3 causeenergization thereof while solenoid S1 is deenergized and this willcause retracting movement of the carriage. Switch L52 is adapted forbeing opened when the carriage reaches its retracted position thushalting the retracting movement.

Push button 268 is by-passed -by a limit switch L53 which may bepositioned to be closed by the carriage at a predetermined advancedposition and thus initiating the retraction of the carriage.

The previously mentioned pressure switch 1162 has a normally open bladeby-passing push button 2% and also has a normally open blade in circuitwith timer T which controls blade T1 and which has its own holding bladeT2.

When the pressure supplied to switch 162 is reduced to a predeterminedvalue indicating that the carriage is encountering a predeterminedresistance, the blades of pressure switch ldZ will close therebyenergizing relay R3 and initiating retracting movement of the carriage.Simultaneously timer T will be energized and after a brief interval willopen blade Tl thereof momentarily thereby to halt the retractingmovement of the carriage and also blade T2 will open to de-energize thetimer,

Retracting movement can be resumed by closing push button 2% to preventthe timer T from again becoming energized, and is in circuit with anormally open blade 2li? of relay R2.

Further, in order to insure that the pressure switch will not againbecome operative after the momentary retraction, it is in circuit with athird timer blade T3 which closes only while timer T is energizedwhereupon at the termination of the momentary retracting movement, thepressure switch becomes ineiective for again energizing relay R3.

It will be understood that this invention is susceptible to modificationin order to adapt it to different usages and conditions, andaccordingly, it is desired to comprehend such modiiications within thisinvention as may fall within the scope of the appended claims.

I claim:

1. In a machine tool; a bed having spaced ways, a generally rectangularslide on the ways having side edges adjacent the opposite sides of saidbed and also having front and back ends, racks on the bed parallel withthe ways and adjacent the side edges of the slide, pinions on the slideat each end thereof and at both side edges thereof meshing with theracks, a pair of differential units on the slide each locatedintermediate: the side edges of the slide and each having a pair ofoutput members extending in opposite directions therefrom and connectedwith the pinions at one end of the slide and each said unit also havingan input member extending therefrom toward one side edge of the slide,hydraulic motors mounted on the slide and connected with said inputmembers, a source of fluid under pressure, a reversing valve connectingthe source of tluid with said motors, said motors being connected inparallel, a choke valve and 7 check valve in parallel between thereversing valve and one side of said motors, a twoway valve connectedbetween the reversing valve and the other side of said motors, andanother two-way Valve connected between the said one side of said motorsand exhaust.

2.1n a machine tool; a bed having spaced Ways, a generally rectangularslide on the ways having side edges adjacent the opposite sides of saidbed and also having front and back ends, racks on the bed parallel withthe ways and adjacent the side edges of the slide, pinions on the slideat each end thereof and at both side edges thereof meshing with theracks, a pair of diterential units on the slide each locatedintermediate the side edges of the slide and each having a pair ofoutput members extending in opposite directions therefrom and connectedwith the pinions at one end of the slide and each said unit also havingan input member extending therefrom toward one side edge of the slide,hydraulic motors mounted on the slide and connected with said inputmembers, a source of fluid under pressure, a reversing valve connectingthe source of Huid with said motors, said motors being connected inparallel, a choke valve and check valve in parallel between thereversing valve and one side of said motors, a twoway valve connectedbetween the reversing valve and the other side of siad motors, andanother two-way valve connected between the said one side of said motorsand exhaust, each of said valves being independently operable wherebythe motors can be driven rapidly in either direction, or at reducedspeed in one direction, or can be locked against rotation.

3. An arrangement according to claim 2 in which there is a gearedtransmission connecting each said hydraulic motor with its pertaininginput member, and each said geared transmission including reversinggears whereby the said reduced speed of operation can be ob tained ineither direction of movement of said slide on the ways, each said gearedtransmission being carried by the slide at the side edge thereof.

4. In a machine tool; a bed having spaced slide supporting ways, agenerally rectangular slide slideably mounted on the said ways andhaving side edges adjacent the sides of said bed and also having frontand back ends, racks on the bed parallel with the said ways and adjacentthe side edges of the slide, pinions on the slide at each end thereofand at both sides thereof meshing with said racks, a pair ofdifferential units mounted on the slide, each said unit having a pair ofout put members connected with the respective pinions at one end of theslide, each said unit also having an input member, a hydraulic motor onthe slide for each differential unit and connected with the input memberof the respective unit, said hydraulic motors being connected inparallel, a source of fluid under pressure, a reversing valve connectingthe source of fluid with said motors, a choke valve connected betweenthe reversing valve and one side of said motors, a check valve connectedin parallel with said choke valve and opening toward said motors, atwo-way valve connected between the reversing valve and the other sideof said motors, and another twoway valve connected between the said oneside of said motors and exhaust.

References Cited in the tile of this patent Ul` lTED STATES PATENTS895,661 Morrison Aug. 11, 1908 1,298,060 Krieg Mar. 25, 1919 1,810,747Benzon lune 16, 1931 2,181,055 Hirvonen Nov. 21, 1939 2,360,118Gallimore et al. Oct. 10, 1944 2,679,678 Stephan Ian 1, 1954 2,690,205Stary Sept 28, 1954 2,788,679 Mott Apr. 16, 1957 2,900,846 Lehman Aug.25, 1959 2,952,065 Riedel Sept. 13, 1960 2,969,698 Carlstedt Ian. 31,1961

